At Home Living: Three plants you never want to grow

So a guy walks into a nursery and sees a selection of plants on clearance; Rhododendron, 25-percent off; Philodendron, 50-percent off; and Toxicodendron, 90-percent off. I’ll gladly take the first two, but something about that last one sounds a bit ominous, don’t you think? That’s because Toxicodendron is the plant genus to three of the most hated plants in North America: poison ivy, poison oak and sumac. You couldn’t pay me to take those plants, nor should you. Fortunately no sane nursery owner would ever offer them for sale.

If you’ve had one allergic reaction from any of these plants, more will likely follow with each new exposure. For those of you yet to experience this misery, don’t gloat ... your time may still be coming. My mother-in-law experienced her first allergic reaction to poison ivy this past week.

In fact, only one percent of the U.S. population is considered truly immune. You can’t get the allergic reaction to poison ivy on the first exposure. Although it may happen on the second encounter, most of the time, it is years of repeated, mild exposure that ultimately leads to that “first time” outbreak.

Unless you reside in Hawaii, Alaska or parts of the desert, at least one of these plants grows where you live. Poison ivy is usually found east of the Rockies while poison oak is most common up and down the west coast and southeast. Poison sumac is common in uninhabited swampy areas, primarily along the eastern states. With summer in full swing, these plants are nearly everywhere, especially in untamed, semi-shaded areas. Proceed with caution.

Regardless of what you call it, these plants pack a powerful punch. The active ingredient that leads to days or weeks of itching, oozing blisters is urushiol (pronounced u-ROO-she-ol). It’s located in the sap of the plant. Simply brushing up against an intact plant won’t cause a reaction. That’s the good news. The bad news is that the plants are very fragile. The slightest abrasion from insects, animals or even the wind can release this toxic oil.

The good news is you must have direct contact with the oil to have an outbreak. The bad news is urushiol is a highly persistent oil. It can remain potent for years _ even on dead plants! Although avoiding direct contact is a great first defense, it’s not a guarantee that you won’t still get it. Because the oil easily sticks to everything that touches it, this high mobility makes even couch potatoes vulnerable.

If you happen to handle a garden tool, a ball or toy or even a pet that has made direct contact with the oil, you can get it too. Ironically, most animals, including cats and dogs are not allergic to urushiol.

Next week I’ll follow up with a companion article to let you know the best ways to deal with exposure to these plants. Until then, proceed with caution. With summer in full swing, these plants are everywhere, especially in untamed, semi-shaded areas.